A Study for Effect on the Power Consumption Reduction of ESS Constant Temperature System with Phase Change Material

Abstract

Li-ion batteries are mainly used in energy storage system (ESS) systems, but they have the issue of significant battery fire incidents. Many thermal management technologies to respond to the heat load of batteries using phase change material (PCM) have been studied. We studied the thermal and power consumption properties depending on the charge/discharge and outside temperature of the ESS battery room through field survey data and an experiment. First, data for the heat pump power consumption and various temperature points of an ESS system were measured daily in the commercial operation of a 250 kWh PV-ESS for a year. Correlation analysis of the power consumption of a heat pump cooling and heating operation to maintain the temperature in the ESS battery room shows that the outside air temperature is the major factor. Furthermore, we conducted an experiment to determine the properties of temperature and power consumption by season at a fabricated ESS battery room with a 250 kWh Li-ion battery including 23°C PCM modules. PCM supports cooling and heating to maintain the room temperature as the heat pump operation cycles on and off. The ESS with applied PCM shows a reduction of heat pump power consumption and improved thermal management according to the load of the heating battery for charging/discharging and the day/night outside air temperature. The power consumptions for heating and cooling due to the battery heat load with a charging and discharging capacity of 150 kWh for each season condition for the only-heat-pump and PCM-applied system operations are 5.6 kWh and 0.88 kWh for changing seasons, 16.5 kWh and 15.8 kWh for summer, and 14.3 kWh and 12.2 kWh for winter, and the ratios of the power reductions are 84%, 3%, and 14%, respectively.